Device delivers medication attached to damaged heart

Therepi's reservoir, which can attach directly to the damaged heart tissue, is placed on a dime for size reference. Photo courtesy of Nature Biomedical Engineering/MIT

June 12 (UPI) -- Researchers have developed a small device that attaches to a damaged heart and delivers medication as needed.

To end scarring in the organ where a blood vessel was blocked after a heart attack, researchers engineered a device called Therepi that contains a reservoir of medicine. Researchers from Massachusetts and Ireland published their findings Monday in Nature Biomedical Engineering.

The device's reservoir can be implanted in one surgical procedure, and therapies can be injected by the patient or a healthcare professional.

"After a heart attack we could use this device to deliver therapy to prevent a patient from getting heart failure," co-first author Dr. Ellen Roche, an assistant professor at MIT's Department of Mechanical Engineering and MIT's Institute for Medical Engineering and Science, said in a press release. "If the patient already has some degree of heart failure, we can use the device to attenuate the progression."

Two common systems now used to deliver therapies to prevent heart failure are inefficient and invasive, the researchers said. Drugs are delivered throughout the system rather than where the damage is located, often only a small amount reaches the damaged heart tissue and there are side effects.

"From a pharmacological point-of-view, it's a big problem that you're injecting something that doesn't stay at the damaged tissue long enough to make a difference," co-first author William Whyte, a Ph.D. candidate at Trinity College Dublin, said.

Therepi administers localized, non-invasive therapies as often as needed.

The reservoir, which is made out of a gelatin-based polymer, has a half-spherical shape with a flat bottom attached to the diseased tissue. The flat bottom's semi-permeable membrane can be adjusted to allow more drugs or larger materials to pass into the heart tissue.

"The material we used to construct the reservoir was crucial," Whyte said. "We needed it to act like a sponge so it could retain the therapy exactly where you need it. That is difficult to accomplish since the heart is constantly squeezing and moving."

The reservoir can administer stem cell therapies that promote healing in the damaged heart tissue.

Researchers administered multiple doses of cells to a damaged rat's heart over four weeks. Using a pressure volume catheter and echocardiography, they compared functional changes.

The hearts with multiple dosages of cells via therapy had more cardiac function compared with those with a single injection or no treatment.

"We saw that the groups that had our device had recovered some heart function," Claudia Varela, a Ph.D. student in the Harvard-MIT Division of Health Sciences and Technology, said.

The researchers see potential in different medical conditions.

"The device is really a platform that can be tailored to different organ systems and different conditions," Varela said. "It's just a great example of how intersectional research looking at both devices and biological therapies can help us come up with new ways to treat disease."

And researchers said ultimately the device can determine the best doses.

"As a pharmacist by training, I'm really excited to start investigating what the best dose is, when is the best time to deliver after a heart attack, and how many doses are needed to achieve the desired therapeutic effect," Whyte said.

In 2017, researchers at the University of North Carolina published a study on how it's possible to change scar tissue cells into heart muscle cells.

They used single cell RNA sequencing technology, mathematical modeling as well as genetic and chemical approaches to detail step-by-step molecular changes from fibroblast to cardiomyocyte.